Integration of new network topologies into a cellular network gains more and more attraction and interest both in industry and academy of telecommunications. Good examples are, for example, current study item of heterogeneous networks (which is a deployment of macros, micros, picos, femtos and relays in the same spectrum) in Long Term Evolution (LTE)/LTE-A of the 3rd Generation Partnership Project (3GPP). One step further is to enable heterogeneous local communications directly among devices and machines under supervision of the network. Heterogeneous in local domain may include:                Network controlled device-to-device (D2D) communication including communication in the clusters of devices;        (Semi-)Autonomous D2D communication in a cellular network;        Grid/group of local machines communicating with each other while performing certain tasks in a cooperative way;        Advanced cellular device acting as a gateway for a bunch of low-capability devices or machines to access a network; and        Co-operative downloading or multicasting within a cluster of devices/machines.        
In current cellular networks, a base station (BS), as a centralized controller, is the only access point for user equipments (UEs) such as mobile devices to the network service. Mobile devices can only communicate with a certain BS via the cellular uplink or downlink. However, enabling D2D direct communications when mobile devices are close to each other may offer many advantages, which comprise longer battery life, more efficient resource usage, coverage extension, lower interference level and so on. More recently, using the D2D technology in combination with cellular networks is becoming a promising concept. In such D2D enhanced cellular system, D2D direct communications could benefit from the centralized architecture of the cellular networks. In addition, the efficiency of the conventional cellular systems can be greatly improved by exploiting the higher channel quality of D2D direct links.